Recent medical reports show that dietary intake of olive oil (a fruit oil) in place of butter, margarine and even vegetable oil can result in certain health benefits. For example, olive oil is not only cholesterol-free itself, but in fact has a serum cholesterol lowering effect (especially of low density lipoprotein (LDL), the bad cholesterol). One study shows that inclusion of olive oil in the diet stimulates cholesterol excretion from the small bowel, which may explain the cholesterol lowering effect (Bosaeus, I et al., (February 1992) Eur.J. Clin. Nutr. 46 (2):111-5).
An additional health benefit of olive oil is based on its content of monounsaturated fats (70-80% of total fat). Mono-unsaturated fats have been shown to be less susceptible than poly-unsaturated fats (the main constituent of most vegetable oils) to oxidation (in the body or during storage) and generation of peroxidized, free radical containing, fatty acids, which are immune system suppressants, mutagens, carcinogens, and contribute to aging.
Although olive oil has been consumed for over 2,000 years (originally in the ancient cultures of North Africa, the Middle East, and the European Mediterranean countries), its health benefits have only recently increased its consumption and production in the U.S. and abroad.
Olive oil is obtained by crushing and pressing the olive fruit. Olive oils vary in taste, color (related to chlorophyll content) and odor in accordance with the variety of olive, the growing climate, soil conditions, and maturity when picked. Olive oil retains its original quality upon storage for up to about two years, if kept in a cool and dark environment. Olive oil does not require, but is not damaged by refrigeration. Although refrigeration does result in a thickened oil that appears cloudy.
Olive oil has a wider variety of uses than most other edible oils. Because it has a high flash point, it is frequently used for sauteing and frying. It also functions as a shortening in baking and is a key ingredient in the preparation of many marinades and sauces. Unlike vegetable oils, olive oil has a definite taste and thus lends itself to use as a condiment or seasoning for various vegetables, meats, fish, pastas, and other foods.
Margarines and shortenings are currently prepared from polyunsaturated vegetable oils mainly by hydrogenation. Because vegetable oil margarines and shortenings contain little or no cholesterol, they have been advocated as healthier substitutes to butter and lard. However, recent studies have shown that trans isomers of fatty acids formed during hydrogenation, increase the ratio of plasma low density lipoprotein (LDL) to high density lipoprotein (HDL) in the body, thereby increasing the risk of coronary heart disease (Judd, J. R. et al., (April 1994) Am. J. Clin. Nutr. 59 (4):861-8; Ascherio, A. et al., (January 1994) Circulation 89 (1):94-101; Willett, W. C. et al., (March 1993) Lancet 341 (8845):581-5; and Troisi, R. et al., (December 1992) Am. J. Clin. Nutr. 56 (6):1019-24).
The amount of fat that Americans consume has increased by about 25% over the last 60 years. Fats now provide at least 40% of a person's daily caloric intake (Mead, J., et al., Lipids, (1986 Plenum, New York). A healthier substitute to vegetable oil margarines and shortenings is needed.